Creep Buckling Under Varying Loads

1991 ◽  
Vol 113 (1) ◽  
pp. 41-45 ◽  
Author(s):  
N. Miyazaki ◽  
S. Hagihara ◽  
T. Munakata

Creep buckling analyses under stepwise varying loads are performed on a circular cylindrical shell with initial imperfection subjected to axial compression and a partial spherical shell under uniform external pressure. The finite element method is applied to a creep deformation analysis to obtain the critical time when creep buckling occurs. The results show that a linear cumulative damage rule for creep buckling can be well applied to the creep buckling of the circular cylindrical shell, but cannot to that of the partial spherical shell.

1987 ◽  
Vol 109 (2) ◽  
pp. 179-183 ◽  
Author(s):  
N. Miyazaki

The finite element method is applied to the creep buckling of circular cylindrical shells under axial compression. Not only the axisymmetric mode but also the bifurcation mode of the creep buckling are considered in the analysis. The critical time for creep buckling is defined as either the time when a slope of a displacement versus time curve becomes infinite or the time when the bifurcation buckling occurs. The creep buckling analyses are carried out for an infinitely long and axially compressed circular cylindrical shell with an axisymmetric initial imperfection and for a finitely long and axially compressed circular cylindrical shell. The numerical results are compared with available analytical ones and experimental data.


1976 ◽  
Vol 98 (1) ◽  
pp. 75-80 ◽  
Author(s):  
I. Berman ◽  
A. C. Gangadharan ◽  
G. H. Jaisingh ◽  
G. D. Gupta

The effects of variation of elastic-plastic and creep properties of type 304 stainless steel on solutions of two specific inelastic problems are studied in this paper. The problems considered are: 1 – elastic-plastic-creep buckling of a thin cylindrical shell with initial imperfection and sustained external pressure at high temperature; and 2 – creep and fatigue damage in a thin cylindrical shell subjected to cyclic thermal load and constant internal pressure. Some conclusions are drawn as to the relative importance of variations of different material parameters on initial buckling load, creep buckling time and creep and fatigue damage factors.


1971 ◽  
Vol 93 (4) ◽  
pp. 998-1006
Author(s):  
H. S. Ho ◽  
D. P. Updike

Equations describing the stress field and velocity field occurring in a circular cylindrical shell at plastic collapse are derived corresponding to stress states lying on each face of a yield surface for a uniform shell of material obeying the Tresca yield condition. They are then applied to the case of a shell under combined axisymmetric loadings (moment, shear force, and axial force) at one end and uniform internal or external pressure on the lateral surface. For a sufficiently long shell, complete solutions are obtained for a fixed far end, and for a certain range of values of axial force and pressure, they are obtained for a free far end. All the solutions are represented by either closed form or by quadratures. It is shown that in many cases the radial velocity field is proportional to the shear force.


1993 ◽  
Vol 115 (3) ◽  
pp. 268-274 ◽  
Author(s):  
N. Miyazaki ◽  
S. Hagihara

In the present work, analytical and experimental investigations were performed on creep buckling. Special attention was focussed on bifurcation behavior during creep deformation. The finite element method was used to analyze creep buckling of circular cylindrical shells without initial imperfection. The number of circumferential waves obtained from the analyses agrees well with those of the experiments. The present experimental investigation shows that the circumferential waves are suddenly caused near a bulge. It is also found that there is no correlation between the wavelength of the circumferential waves observed at creep buckling and that of the circumferential initial imperfection. Deformation patterns at the bifurcation creep buckling obtained from the analyses are analogous to those of the experiments. It is concluded from the analyses and the experiments that the circumferential waves observed in creep buckling experiments are due to bifurcation buckling during creep deformation.


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